In general, time recorders are used for work management of employees in companies or the like. When, for example, coming into work, leaving the work place, or the like, an employee inserts a time card into the slot of the time recorder. Printed on the front face of the time card is a printing field for printing the time for dates from, for example, the 1st day to the 15th day of a given month, and printed on the back face of the time card is a printing field for printing the time for dates on and after the 16th day of that month. The employee inserts the time card into the time recorder with the time card facing up when the day of work is in a date range from the 1st day to the 15th day, and inserts the time card into the time recorder with the time card facing down when the day of work is on and after the 16th day. When the time card is inserted, the time recorder prints on the time card, the time at which the employee comes into work or the time at which the employee leaves the work place.
When, however, the employee inserts the time card with the reversed front and back faces, the time recorder performs printing on the reversed face to the original face intended for printing. In order to prevent this, the following Patent Literature 1 discloses a time recorder which uses a time card having a cut-out formed at one of the four corners, and which includes a sensor unit that detects the proximities of the right and left edges of the inserted time card. This time recorder is capable of detecting whether the cut-out of the time card is located at the right or the left. Accordingly, the front and back faces of the time card can be determined.    Patent Literature 1: Unexamined Japanese Utility Model Application Kokai Publication No. S63-103169.